[Interpreter] Introduce IncStub and DecStub.

src/interface-descriptors.h

Index: src/interface-descriptors.h
diff --git a/src/interface-descriptors.h b/src/interface-descriptors.h
index 0b765e3b8636eb924f16c86178f3ba41b0f9f035..fe9c0d6c035db535d21718844c9b01d7be6fbb68 100644
--- a/src/interface-descriptors.h
+++ b/src/interface-descriptors.h
@@ -66,6 +66,7 @@ class PlatformInterfaceDescriptor;
   V(Compare)                                  \
   V(BinaryOp)                                 \
   V(BinaryOpWithAllocationSite)               \
+  V(CountOp)                                  \
   V(StringAdd)                                \
   V(StringCompare)                            \
   V(Keyed)                                    \
@@ -631,6 +632,10 @@ class BinaryOpWithAllocationSiteDescriptor : public CallInterfaceDescriptor {
                      CallInterfaceDescriptor)
 };
 
+class CountOpDescriptor final : public CallInterfaceDescriptor {
+ public:
+  DECLARE_DESCRIPTOR(CountOpDescriptor, CallInterfaceDescriptor)
+};
 
 class StringAddDescriptor : public CallInterfaceDescriptor {
  public: